Electric heating apparatus



II I IW I I I IJTh I I I I I I I I I I I l I I I by 0. A. CQLBY. ELECTRIC HEATING APPARATUS.

APPLICATION FILED SEPT-9, 1916- Patented Mar. 30 192M INVENTOR A. Colby.

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DEW I I elevational view of a portion of the struc- UNITED STATES PATEN ORA. A. COLBY, OF LARIM'ER, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, CORPORATION OF PENNSYLVANIA.

ELECTRIC HEATING APPARATUS.

Specification of Letters Patent.

I Patented Mar. 30, 192a.

Application filed September 9, 1916. Serial No. 119,234.

' Larimer, in the county of Westmoreland and State of Pennsylvania, have invented a new and useful Improvement in Electric Heating Apparatus, of which the following is a specification.

My invention relates to electric heating apparatus and it has special relation to air heaters, oven heaters and other devices in which the heating element consists of an exposed body of resistance material carried upon suitable supports in such a manner as to provide free circulation of air around ,the resistance conductor.

One of the objects of my invention is to provide a heating device of the above-indicated character which shall be of simple and inexpensive construction and which shall be provided with an improved arrangement of terminal connections. I 7

Another object of my invention is to provide a heating device of the above-indicated character in which the resistance element consists of a strip or ribbon of conducting material wound upon suitably insulated supports, the said supports serving as the terminal conductors of the device.

In the accompanying drawing, Figure 1 showing a heater unit constructed in accordance with my invention. Fig. 2 is a plan view, partially in section, of the structure shown in Fi 1. Fig. 3 is an end ture of Fig. 1, showing one means for attaching the resistance conductor to its support, and Fig. 4 is a fragmentary side elevational view illustrating the use'of a modified form of resistance conductor.

Referring to Figs. 1, 2 and 3 of the drawv ing, the flanged end plates or end supports 1 and 2, which may conveniently be made of bent sheet metal, are provided with suitable apertures through which extend horizontal rods 3 and 4. Both of the rods 3 and 4 carry sets of flanged washers 5 of insulating material which are arranged sideby-side, the two sets of washers forming a 1 series of staggered grooves upon which a ribbon 6 of resistance material is wound in a flattened helix, as shown in Fig. 1. The staggered arrangement of the washers 5 is obtained by means of end washers 7 and 8 which are of unequal thicknesses and are alternately disposed at the ends of the rods 3 and 4, as shown.

Rigid engagement between the rods 3 and 4, the insulating washers carried thereon and the end supports 1 and '2 is 'efiected by means of washers and nuts arranged as best shown in section in Fig. 1 and comprising a washer 9 of insulating material having a sleeve portion extending through an opening 10 in the end plate 2 into a circular de pression in the adjacent washer 7. The

washer 9 is forced against the wall of the I I support 2 by means of a nut 11 held in -place by means of a lock nut 12. v

The ends of the resistance ribbon 6 are attached directly to the rods 3 and 4 at points near their diagonally opposite ends. This attachment may be efiected in any suitable manner, conveniently by means of clamps which, as best shown in Fig. 3, consist of a pair of similar members 13 and 14, curved to fit the rods 3 and 4 and firmly grasping the end of the ribbon 6. A screw 15 and a nut 16 secure the two parts of the clamp together. A

-'required number of washers upon the rods 3 and 4, passing the ends of the rods through the openings 10 in the end plates 1 and 2 and applying the washers 9 to the ends 0 the rods. The resistance ribbon is then wound upon the washers and secured, by means of the clamps described above, to the rods 3 and 4, and all of the parts are secured .in rigid relation by tightening the nuts 11 and 12. v

Suitable terminal connections are. at-- 7 tached to the rods 3 and 4, which, it'will be observed, serve as terminal conductors for the resistance'ribbon 6. Such terminal; attachments are shown at 17 and 18 and are readily attached to the rods by means ofthe' nuts 11 and 12. It will be particularly observed that the terminals 17 and 18 are disposed at opposite ends of the resistance unit, an arrangement which facilitates the use of these units in groups of two or more. desired, both of the terminals may be attach'ed to the supporting rods at the same steel alloy such as nickel-steel, silicon steel or the like, or of any other suitable resistance material. The resistance strip shown at 19 in Fig. 4 diflers from that shown in the first-described figures, in that it is slotted, as shown at 20, to produce a large number 5 of parallel conducting paths and thereby to increase the heating effect. The slots formed in the ribbon 19 are such as are made in'sheetmetal preparatory to expanding the metal, and it will be evident that the ribbon may be expanded, if desired, before being wound upon its supports. The ribbon maybe otherwise slotted or modified in any desired mannerand it may be of any suitable width and thickness. T find it convenient to employ wider ribbon for the 170 all forms of resistance element, whether such elements be in the form of strips, wires, rods or plates.

lit will be understood that the structural details of my device may be otherwise variously modified without exceeding the limits of my invention and I accordingly desire that no limitations be imposed upon my invention except such as are indicated in the appended claims.

I claim as my invention:

1. A resistance device for electric heating apparatus and the like comprising a supporting frame consisting of spaced supporting elements, conductor rods mounted on, and insulated from, said supporting elements, each of said rods being covered with insulating material over a greater portion of its length and each rod also having means thereon whereby a current-supply conductor may be secured thereto, a resistance conductor extending in a plurality of convolutions around portions of both of said rods covered by insulating material, and means for electrically connecting one end of said resistance conductor to one of said rods and the other end of the same to another of the rods whereby the rods to which the resistance conductor is connected serve as termi nal conductors for the opposite ends of the resistance conductor and also as supporting means for the resistance conductor.

2. An electric heating apparatus comprising a supporting frame consisting of spaced supporting elements and two spaced parallel conductor rods mounted on, and insulated from, said supporting elements, insulating washers carried by said rods and covering the greater portions of the rods between said supporting elements, a resistance strip between said supporting elements extending in a plurality of convolutions around the washers on said rods, means for electrically connecting one end of said strip to one rod, means for electrically connecting the other end or" said strip to the other rod, and terminal members secured to said rods.

3. A resistance device for electric heating apparatus and the like comprising a plurality of: supporting members of conducting material, a resistance conductor carried by the said supporting members and insu lated therefrom over thegreater portion of the length of said supporting members, and means for electrically connecting the said supporting members to the said resistance conductor whereby said supporting numbersserve as terminal conductors for the opposite ends of the resistance conductor.

4:. A resistance device for electric heating apparatus and the like comprising two end plates, two parallel supporting members of conducting material extending through, and insulated from, said end plates, a resistance element of conducting material extending in a plurality of convolutions around both of the said supporting members and insulated therefrom except at its ends, the said ends being electrically connected to the said supporting members, and contact terminals mounted on said supporting members outside of said end plates.

5. A resistance device for electric heating apparatus and the like comprising spaced end plates, two spaced members of conducting material supported in apertures in said plates but insulated therefrom,-a resistance conductor extending in a plurality of convolutions around said members and insulated therefrom except at its ends, the said ends being electrically connected to the said conducting members whereby the latter serve as tcrminalconductors for the opposite ends of the resistance conductor, and

'means for securing said members and plates together.

6; An electric heating apparatus comprising spaced end plates having apertures therein, insulating bushings in said apertures, two parallel spaced rods of conducting material mounted on said end plates and having ends projecting through said bushings, insulating means covering said rods over a greater portion of their length, a resistance conductor extending in a plurality of convolutions around said insulating members, means on each rod for connecting an portion of their length, a resistance conductor extending in the form of a flattened helix around said insulating members, means on each rod for electrically connecting an end rof said conductor thereto, terminal members carried by projecting ends of said rods, and nuts fitting the projecting threaded ends of said rods for securing said rods and associated parts together.

8. A resistance device for electric heating apparatus and the like comprising two spaced end plates having apertures therein, two parallel supports consisting of rods of conducting material extending through said apertures and insulated from the plates, flanged insulating washers carried thereby, a resistance ribbon extending ina plurality of convolutions around both of the said supports and received between the flanges of 23 the said washers, means for electrically connecting the ends o'f'the vsaid resistance ribbon to the said supports, and terminal members secured to the said supports.

9. A resistance device forelectric-heating 'apparatus comprising two spaced flanged end plates having apertures therein, two parallel supporting rods of conducting material passing through said apertures and insulated from said plates, a slotted resist In testimony whereof I have hereunto subscribed my name this 7th day of Sept,

ORA A. COLBY.

and terminal connectors- 

